Fishtail point for augers



Jan: 24, 1933; Q m 1,895,205

FISHTAIL POINT FOR AUGERS Original Filed Sept. 12. 192-? 5 gmm toz Patented Jan. 24, 1933 y UNITED STATES PATENT" FF CE FRANK OSCAR PRIOR, or TULSA, OKLAHOMA, AssIGNO T0 FOU WHEEL DRIVE UTO COMPANY, OF CLINTQNVILLE, wIsOoNsIN, A CORPORATION or WISGONSiN.

" FI'sHT IL POINT FOB. AUGRRs Original a ncatio'n filed September 12,1927, Serial No. 219,051. Divided and this application filed January 30, 1930. Serial N0. 424,534. e I I J This invention relates to improvements fish-tail points for augers.

It is the particular purpose of the inven tion to provide a point for earth boring auger adaptable to be used in shale, loose rock, or gravel; In an earth boring auger the ordinary point is not suitable in that it fails to include adequate means for cutting and breaking material at the center of the hole. The present invention seeks to overcome the deficiencies of previously known points in this regard.

Fish-tail bits are well known in the earth boring art. The present invention relates to a specific form of cuttingsurface of a fish-tail bit, and moreparticularly it relates to a novel relation of cutting edges and bevelledsurfaces on the Working end of the bit.

It is an object of the'invention to provide a bit having a work ng surface and cutting edges of such form that grinding thereoffincluding the original manufacturing operation and subsequent sharpening of the bit, may be accomplished with greater fac lity than with bits made in accordance with the teaching of the prior art." The entire working face of my bit may be sharpened one continuous Operation, wh ch. is impossibl with fish-tail bits of the prior art.

' In the drawing:

Figure 1 shows a perspective'view in elevation; of an improved point embodying this invention.- r

Figure 2is a front elevation of the lower end of thepoint shown in Fig. 1. a a

Figure?) is a side elevat on of the lower end'of the'pointshown in Fig. 1. a This applioationis' a division ofmy appli- .cation 219,051 in which I have shown a complete earth boring auger having a point embodying this invention. y

The fish-tail point herein disclosed is made of a fiat pieceof stock 12 which is comparatively thin and has side margins flaring at 13 and 14 to form pointed teeth at the lower corners. The lower margins of the plane 1 V sides of the auger point are oppositely inclined with reference to the central axis of the point and are preferably substantially" straight lines,,each of which defines the base of one tooth and the cutting edge of the other. The margin 15 forms the base .of tooth 13 and the cutting or leading edgeof tooth 14:, whereas margin 16 comprises the cutting or leading edge oftooth 13 at the y base or root of tooth 14, Th s construction g ves the teeth a peculiar rolling bevel and it is found-that flaring teeth so beveled have great adaptability for performing thefunctions of cutting and breaking shale [and the like in add tion to the normal function of guiding the-auger. I 5

It will be seen that the lower surface of the bit may be described as having been generated by moving a generatrix line in a directrix normal to the front face ofithe b t and intersecting the axis thereof and simultaneously swinging the generatrix about the directrix as an axis sothat the ends of the generatrix follow two oppositely disnosed obl que directrices which constitute lateral edges ofthe surface; or, considered from another point of view, the surface might be described as having been generated by moving a line from left to-right of Figure 1 along a central line normalto the narrow surfaces of the piece of stock 12 and 2 simultaneously swinging the about said normal as an axis and using the edges 15, 16 as secondary directrices for the generatrix to control the extent to which the latteris swung. It will be readily apparent, to one skilled in the art that such a surface presents marked advantages from the po nt of view of sharpening, because the entire working surface of the bit may be sharpened by merely causing a relative movement between the bit and grinding wheel corresponding to the movement of the above described generatrix. Consequently, the entire generatrix i bit may be sharpened evenly and accurately in a single operation.

In devices of the priorart, it has been necessary to sharpenthe two cutting surfaces tion invariably follow an unsymmetrical grinding of a fish-tail bit. Consequently, it is an object of my invention to: produce'a bit which will always be sharpened with perfect symmetry, thus eliminatingthe-possibility of faulty operation after extensive use.

At its upper end the stock or body member 12 of the point is shouldered at 17 and 18 to provide a tongue-like extension 19 pierced by a; hole through which a securing bolt may be extended to anchor-the pointtothe auger.

I claim:

1. A fish-tail auger point comprising a platehaving its lower end provided with a rolling-bevel varying substantially continuously in angle of inclination from one side i so of the'plate to the other, and having straight line edges extending entirely across said plate the bevel of said lower end being opposite in angle. of inclination at opposite side margins of the plate.

2.'A fish-tail auger point comprising a relatively thin elongated plate having one of itstends provided with rectilinear edges coextensive witlrthewidth of'said plate, said end being beveled atopposite angles of inclination at the opposite sides of the plate, the bevel of the end of'tlie plate I'OlllIlg'Sllbstantially continuously between the sides of the plate, and the angles of'inclination of the oppositely beveled portions at the marglns thereof being. substantially alike.

' 3..A fish-tail auger point, comprising a plate having its opposing faces terminating in marginsiof opposite inclination and teeth formed in the corners of said plate by the inclination of'such margins, each margin lying'in a straight line defining the leading edge of one tooth and the base of the other.

,4. A fish-tail auger po nt comprising a substantially flat plate flaring at its lower end and'provided at such end with a substantially symmetrical. rolling bevel surface of substantially equal and opposite inclination at the opposite sides ofithe plate and varying substantially continuouslytherebetween, the margins of said surface lying in stra ght line edges extending substantially across said plate. I I 7 5. A fish-tail auger point comprising a substantially flat plateiflaring at thesides of its lower end andprovided at such end with oppositely beveled portions terminating in points at the opposite sides of the plate, said oppositely bevelled portions being bounded by substantially straight edges extending entirely across said'plate.

6. A fish-tail auger point comprising a flat plate having flaring margins adjacent its lower end, the lower margins of adjacent faces of said plate being oppositely inclined whereby to form teeth at the, flaringv corners of the plate, each such margin extending in a substantially continuous straight. line across-said plate and definingvthe.v leading edge of one tooth and theroot of'thev other.

7 A fish-tail auger point comprising a fiat platehaving flaring margins adjacent its lower end, the lower margins of adjacent faces of said plate'being oppositely inclined whereby to form teeth at the flaring corners of the plate, each such margin defining the leadingedge of one tooth and theroot ofthe other, and each such margin beingsubstantially linear whereby toprovide a substantially continuous rolling bevelacross the lower end of the plate;

8. fish-tail bit having two substantially parallel plane faces, each'of said faces terminating in a continuous straight line edge extending the full width of said bit,sai'd: two

edges being oppositely inclined'to-the axis of said bit, saidbit' having a bottomsurface connecting the said edges and varyingin angular relation to said planesurfaces constantly throughout the full width of. saidibit.

9. A fish-tailbit comprising a substantially flat plate terminating, in outwardly" flaring points at its lower end, said bit having substantially parallel side faces and; a bottom face, said side faces meeting said bottom face in straight line edges extending the full width of said bit from one to the other of said outwardly flared points, said straight line edges beingoppositely inclined to: the axis of said bit throughout their entire lengths, said bottom face presenting'a constantly varying rolling bevelled surface from one of said points to the other.

10. A fish-tail bit comprising a substantially flat plate having substantiallyparallel side facesand having a bottom surface, said f 1 surface being generated by passing a straight line generatrix along and in perpendicular relation to a central directrix normal to saidfaces and intersecting the axis of said bit, and simultaneously swinging said generatrix abput said directrix to cause its ends to follow oppositely disposed obliq'ue directrices, of which; latter directrices one is spaced at each side of sa d first directrix, and defines an edge of said surface 11. A fish-tail bit comprising a substantially flat plate having substantially parallel side faces and having a bottom surface, said surface beinggenerated by passing a straight line generatrix along and in perpendicular face.

FRANK OSCAR PRIOR. 

